Genus Erwinia: Numerical Analysis of Phenotypic Features

Abstract

API 20E and API SOCHE systems (72 phenotypic tests) were applied to a total of 529 strains, including 421 strains belonging to 21 different Erwinia species, 66 Enterobacter agglomerans strains, 18 Escherichia adecarboxylata strains, and 24 strains of 16 other enterobacteria. The results were analyzed numerically by using the Gower similarity coefficient and the unweighted average linkage method. The named Erwinia strains were distributed over 27 phena, some of which also contained strains received as Enterobacter agglomerans. Strains of Erwinia amylovora, Erwinia chrysanthemi, Erwinia cypripedii, Erwinia mallotivora, Erwinia nigrijiuens, Erwinia paradisiaca, Erwinia quercina, Erwinia rubrifaciens, Erwinia salicis, Erwinia stewartii, and Escherichia adecarboxylata constitute separate phena. Erwinia carotovora, Erwinia chrysanthemi, and Erwinia rhapontici are heterogeneous, but distinct from each other and from the other phena. The type strains of Erwinia herbicola, Enterobacter agglomerans, and Erwinia milletiae fall into one phenon, and strains of Erwinia ananas and Erwinia uredovora are in a single phenon. Obviously misnamed Erwinia herbicola and Enterobacter agglomerans strains can be assigned to other species, such as Erwinia cypripedii, Erwinia ananas, Erwinia rhapontici, Rahnella aquatilis, Enterobacter sakazakii, Escherichia adecarboxyluta, and Serratia marcescens or to as-yet-unnamed phena. Three Erwinia carnegieana strains, but not the type strain, form one phenon. Erwinia dissolvens and Erwinia nimipressuralis should be allocated to Enterobacter. Our results confirm the heterogeneous taxonomic structure of the genus Erwinia.According to Lelliott and Dickey (41), the genus Erwinia consists of 15 species that are associated with plants as pathogens, saprophytes, or epiphytes. Erwinia herbicola also includes human clinical isolates. There are 21 Erwinia species names on the Approved Lists of Bacterial Names (58).Several attempts have been made to clarify the taxonomic structure of Erwinia; these have been based on different methodologies, such as deoxyribonucleic acid (DNA)-DNA hybridization (2, &lo, 29,32,47), comparative phenotypic studies (17,(21)(22)(23)(24)(25)27,30,45,67), serological studies (11,19,59,60,72), gel electrophoresis of proteins (43,44,46,69), and characterization of the respiratory quinones and enzymes of fumarate metabolism (32). The problems related to the taxonomy of Erwinia have been discussed extensively (5 , 41, 45, 63, 65). These problems are based mainly on the heterogeneity of the genus Erwinia, as reflected in (i) the (former) subdivision of Erwinia into three "natural groups" based on phytopathological characteristics (21-25, 40), (ii) the unclear delineation of some species, such as Erwinia carotovora and Erwinia herbicola, due to their internal heterogeneity (4, 45, 63, 65), and (iii) the existence of an "Erwinia herbicola-Enterobacter agglomerans complex," with unclear relationships among its members and with other taxa of the Enterobacteriaceae (4).Because of the inadequa...

Genotypic Relationships and Taxonomic Localization of Unclassified Pseudomonas and Pseudomonas-Like Strains by Deoxyribonucleic Acid:Ribosomal Ribonucleic Acid Hybridizations

“…Thus, our results do not contradict the proposed and generally accepted inclusion of " [Pseudomonas] trifolii" in Erwinia herbicolu (33). Recently, Verdonck et al (56) showed that this strain belongs phenotypically in Erwinia herbicola phenon 9. The position of leaf nodule organism LMG 2806 has been discussed previously in more detail (16).…”

Pantoea vagans sp. nov., Pantoea eucalypti sp. nov., Pantoea deleyi sp. nov. and Pantoea anthophila sp. nov.

“…However, both 16S rRNA gene sequencing and MLSA support the phylogenetic delineation of P. vagans from P. agglomerans. Past studies have highlighted the difficulties in identifying Pantoea strains based on phenotypic data (Beji et al, 1988;Brenner et al, 1984;Mergaert et al, 1984;Verdonck et al, 1987), and it has been suggested that caution be exercised when basing identification solely on commercial phenotypic identification systems (Gavini et al, 1989). Despite the high phenotypic similarity within the genus Pantoea, several biochemical characteristics were recognized that could distinguish the four novel species from each other and from their closest phylogenetic neighbours.…”

Emended description of the genus Pantoea, description of four species from human clinical samples, Pantoea septica sp. nov., Pantoea eucrina sp. nov., Pantoea brenneri sp. nov. and Pantoea conspicua sp. nov., and transfer of Pectobacterium cypripedii (Hori 1911) Brenner et al. 1973 emend. Hauben et al. 1998 to the genus as Pantoea cypripedii comb. nov.

“…Since the early 1970s, various attempts have been made to clarify the Erwinia herbicola-Enterobacter agglomerans complex (Ewing & Fife, 1972;Gardner & Kado, 1972;Young et al, 1978;Dye, 1981;Brenner et al, 1984;Verdonck et al, 1987;Beji et al, 1988). The most comprehensive study to date was performed by Brenner et al (1984), who separated 124 strains belonging to this complex into 13 groups based on their DNA-DNA hybridization relatedness.…”